Does the Meguma Terrane Extend into SW England?

The peri-Gondwanan Meguma terrane of southern Nova Scotia, Canada, is the only major lithotectonic element of the northern Appalachian orogen that has no clear correlatives elsewhere in the Appalachians and lacks firm linkages to the Caledonide and Variscan orogens of western and southern Europe. This characteristic is in contrast with its immediate peri-Gondwanan neighbor, Avalonia, which has features in common with portions of Carolinia in the southern Appalachians and has been traced from the Rhenohercynian Zone of southern Britain eastward around the Bohemian Massif to the Carpathians and western Pontides. At issue is the tendency in Europe to assign all peri-Gondwanan terranes lying outboard of the Rheic suture to Avalonia, characterized by relatively juvenile basement and detrital zircon ages that include Mesoproterozoic populations, and those inboard of the suture to Cadomia, characterized by a more evolved basement and detrital zircon ages that match Paleoproterozoic and older sources in the West African craton.    Although the unexposed basements of Avalonia and Meguma are thought to be isotopically very similar, the Meguma sedimentary cover contains scarce Mesoproterozoic zircon and is dominated instead by Neoproterozoic and Paleoproterozoic populations like those of Cadomia. Hence, felsic magma produced by crustal melting in the Meguma terrane (e.g. the ca. 370 Ma South Mountain Batholith) is isotopically more juvenile (eNd = –5 to –1, TDM = 1.3 Ga) than the rocks it intruded (eNd= –12 to –7, TDM = 1.7 Ga). By contrast, felsic magma produced by crustal melting in Avalonia (eNd = –1 to +6, TDM = 0.7–1.2 Ga) is isotopically similar to its host rocks (eNd = –3 to +4, TDM = 0.9–1.4).    The isotopic relationship shown by the Meguma terrane has also been recognized in the South Portuguese Zone of southern Spain, which is traditionally assigned to Avalonia. However, the Sierra Norte Batholith of the South Portuguese Zone (ca. 330 Ma; eNd = +1 to –3, TDM = 0.9–1.2 Ga) is on average more juvenile than the Late Devonian host rocks (eNd = –5 to –11) it intruded, suggesting instead an extension of the Meguma terrane into Europe. Available data for the Cornubian Batholith of SW England (ca. 275–295 Ma; eNd = –4 to –7, TDM = 1.3–1.8 Ga) and the Devonian–Carboniferous metasedimentary rocks it intruded (eNd = –8 to –11) suggests this may also be true of that part of the southern Britain (Rhenohercynian Zone) with which the South Portuguese Zone is traditionally correlated.SOMMAIRELe terrane péri-gondwanien de Meguma en Nouvelle-Écosse au Canada, est le seul grand élément lithotectonique de l’orogène des Appalaches du Nord qui n’ait pas de correspondant avéré ailleurs dans les Appalaches et qui ne montre aucun lien sûr avec les orogènes calédonienne et varisque de l’ouest et du sud de l’Europe.  Cette situation contraste avec celle de son voisin péri-gondwanien immédiat, l’Avalonie, qui partage certaines caractéristiques avec des portions de Carolinia des Appalaches du sud et qui a été suivi à partir de la zone rhénohercynienne dans le sud de la Grande-Bretagne vers l’est autour du massif bohémien jusqu’aux Carpates et l’ouest de la chaîne pontique.  Ce qui est en question ici c’est la tendance en Europe à assigner l’Avalonie à tous les terranes péri-gondwaniens situés à l’extérieur de la suture rhéïque lesquels sont caractérisés par un socle relativement juvénile et des âges de zircons détritiques qui comportent des populations mésoprotérozoïques, et ceux situés à l’intérieur de la suture à Cadomia, lesquels sont caractérisés par un socle plus évolué et des âges de zircons détritiques qui correspondent à des sources du craton ouest africain paléoprotérozoïques et plus anciennes.     Bien que l’on estime que les socles non-exposés des terranes d’Avalonie et de Meguma soient très similaires isotopiquement, le couvert sédimentaire de Meguma ne renferme que de rares zircons mésoprotérozoïques, et ce sont plutôt les populations de zircons néoprotérozoïques et paléoprotérozoïques qui dominent, comme c’est le cas pour Cadomia.  Il en ressort que le magma felsique produit par la fusion de croûte dans le terrane de Meguma (par ex. le batholite de South Mountain de 370 Ma env.) est isotopiquement plus jeune (eNd = –5 à –1, TDM = 1.3 Ga) que les roches qu’il recoupe (eNd= –12 à –7, TDM = 1.7 Ga).  Par opposition, le magma felsique produit par la fusion de la croûte dans le terrane d’Avalonie (eNd = –1 à +6, TDM = 0.7–1.2 Ga) est isotopiquement similaire aux roches de son encaissant (eNd = –3 à +4, TDM = 0.9–1.4).     Le profil isotopique du terrane de Meguma, traditionnellement assignée à l’Avalonie,  a aussi été détecté dans la Zone sud-portugaise du sud de l’Espagne.  Cependant, le batholite de Sierra Norte de la Zone sud-portugaise (ca. 330 Ma; eNd = +1 à –3, TDM = 0.9–1.2 Ga) est en moyenne plus jeune que l’encaissant du Dévonien moyen (eNd = –5 à –11) qu’il recoupe, ce qui permet de penser à une extension du terrane de Meguma en Europe.  Les données disponibles du batholite de Cornubian dans le S-O de l’Angleterre (ca. 275–295 Ma; eNd = –4 à –7, TDM = 1.3–1.8 Ga) et des roches métasédimentaires dévono-carbonifères qu’il recoupe (eNd = –8 to –11) permet de penser qu’il pourrait en être de même de cette portion du sud de la Grande-Bretagne (Zone rhénohercynienne) avec laquelle la Zone sud-portugaise est traditionnellement corrélée

A Robust Polyurethane Depositing System for Overcoming Obstacles in Disaster Scenario Robotics

One of the most difficult challenges for terrestrial robotic platforms in disaster scenarios is their inability to traverse highly irregular terrain. Many different robotic architectures have been proposed over recent years, each with benefits and shortfalls. In this work, we propose a Polyurethane Foam depositing system, which can be applied to any such platform and increase its ability to overcome obstacles significantly. The system proposed is inexpensive, and the way in which it overcomes obstacles allows very simple control systems for autonomy. The deposited foam has a potential expansion ratio of over 33 × its constituent parts and a final compressive strength exceeding 2 MPa, final mechanical properties can be tuned on board. The system has been implemented on a two-tracked rover and its autonomous responses tested against significant objects and chasms. The results show that the amount of foam deposited can be well controlled and multiple layers can be stacked on top of each other to significantly increase altitude

Proteolytic inactivation of human α1 antitrypsin by human stromelysin

Abstractα1Antitrypsin (α1AT) is the main physiological inhibitor of neutrophil elastase, a serine protease which has been implicated in tissue degradation at inflammatory sites. We report here that the connective tissue metalloproteinase, stromelysin, cleaved α1AT (54 kDa), producing fragments of approximately 50 kDa and 4 kDa, as shown by gel electrophoresis. The cleavage of α1AT was accompanied by inactivation of its elastase inhibitory capacity. Isolation of the 4 kDa fragment by reversed-phase HPLC, followed by N-terminal amino acid sequencing, demonstrated that the cleavage of α1AT occurred at the Pro357-Met358 (P2P1) peptide bond, one peptide bond to the N-terminal side of the inhibitory site. We suggest that stromelysin may potentiate the activity of neutrophil elastase by proteolytically inactivating α1AT

Ichthyophonus irregularis sp. nov. from the yellowtail flounder Limanda ferruginea from the Nova Scotia shelf

A previously described unusual form of the protistan parasite Ichthyophonus, differing in morphological and developmental features from I. hoferi sensu Plehn & Mulsow, was recovered from yellowtail flounder Limanda ferruginea Storer from the Brown's Bank area of the Nova Scotia shelf. The nuclear gene encoding the rRNA of the small ribosomal subunit was amplified from this unusual form of Ichthyophonus using the polymerase chain reaction, sequenced and aligned with other eukaryote small subunit (ssu)-rDNAs. Inferred phylogenetic trees clearly show that its ssu-rDNA is distinct from those of 2 isolates of I. hoferi sensu Plehn & Mulsow from different hosts and geographical locations (herring in the North Sea, and yellowtail flounder from the Nova Scotia shelf). We consider the unusual form to be a separate species, I. irregularis. The occurrence of a second, distinct type of Ichthyophonus within a single host species raises the possibility that ichthyophoniasis could be produced by different (although related) pathogens, and in some cases, by concurrent infections of the two

Host Species and Captivity Distinguish the Microbiome Compositions of a Diverse Zoo-Resident Non-Human Primate Population

Vast numbers of microorganisms inhabit the mammalian gastrointestinal tract in a complex community referred to as the gut microbiome. An individual’s microbiome may be impacted by genetics, diet, and various environmental factors, and has been associated with many health states and diseases, though specific explanations are lacking. While these communities are well-studied in human populations, non-human primates (NHPs), in particular zoo-resident or captive NHPs, offer distinct advantages to increasing our understanding of factors that influence gut microbiome composition. Here, we characterize the gut microbiome composition of a phylogenetically diverse cohort of NHPs residing in the same urban zoo. We show that despite overlapping and controlled environmental contexts, gut microbiomes are still distinguished between NHP host species. However, when comparing the zoo cohort to wild NHPs, we show that captivity status strongly distinguishes zoo-resident NHPs from their wild counterparts, regardless of host phylogeny. Microbial orders unique to captive NHPs include taxa commonly present in human gut microbiomes. Together, these results demonstrate that differences between NHP species are strongly associated with gut microbiome composition and diversity, suggesting that species-specific approaches should be considered when investigating environmental factors’ influence on gut microbiome composition